The Present invention relates to a method for welding an end plug to a respective open end of a surface-coated tube to produce a control rod.
A surface-coated tube of the type that includes a hard coating layer such as chromium plating formed on an outer peripheral surface of a tube body has recently been employed more frequently for the manufacture of control rods. However, when a conventional tungsten inert gas (TIG) welding is employed to weld an end plug to the open end of the surface-coated tube, the coating material plated on the tube dissolves into the welded portion and consequently the quality of the welding deteriorates.
In order to avoid this problem, the hard coating has not been performed on a portion of the tube body which is proximate to the welding portion. However, this means that the non-coated portion of the surface-coated tube proximate to the welding portion is inferior in wear resistance to the other portion thereof.